The invention refers to a turbomachine comprising a magnetic bearing and a retainer bearing associated to the magnetic bearing.
Turbopumps, such as turbomolecular pumps and turbo-blowers, for example, rotate at very high speeds of up to 80,000 rotations per minute. Therefore, the rotor is preferably supported in magnetic bearings that are especially well suited for high speeds. In the event that the magnetic bearing or bearings fail, so-called mechanical retainer bearings are provided that are to prevent the pump rotor from contacting and thereby destroying the pump stator should the magnetic bearing fail.
The retainer bearings used for turbomolecular pumps are roller bearings that, in contrast with sliding bearings, are less subject to wear for reasons of their structural principle. However, roller bearings are disadvantageous in that they are relatively expensive and may amount to up to 10% of the overall costs of turbomolecular pumps and turbo-blowers.
In view of the above, it is an object of the invention to provide a magnetically supported turbo machine having an economic retainer bearing.